Tripura Hills lies in the middle part of the chittagong-tripura folded belt and falls within the Indian Territory. Five or six ranges of hills with north-south elongation run parallel having an average distance of about 20-km from each other. These ranges and the valleys between them increase in height as they approach the east. The principal hill ranges beginning from the east are - the Jampuri, Sakkanklang, Langtarai, and Athara-mura ranges. The elevation of Tripura Hills varies from 60m to 120m and further east it rises to over 600m. The highest peak, the Betling Sib, is in the Jampuri Range with an elevation of 975m. These hills are composed of sediments of Paleocene through Pleistocene age.
Six hill ranges from the Tripura Hills of India project into the Sylhet district of Bangladesh, south of the kushiyara river, and they have small elevation. From the east to the west, they are Patharia range, Harargaj or Langla hills, Bhanugach or Rajkandi hills, Balisara hills, Satgaon hills, and Raghunandan hills. The Harargaj peak is the highest point in the Sylhet area with an elevation of 336 m above mean sea level. The anticlines of the northern Tripura Hills are north plunging and die out under the overlapping Recent sediments of the Sylhet Basin. The anticlines are faulted and many of them are still active. [AKM Khorshed Alam]